Molecular mechanism of programmed necrosis induced by NLRP3-inflammasome

Tet-on系统表达的MuLRP-3诱导了坏死细胞死亡，而WT则没有。我们发现，CA 074-Me（酪蛋白酶B抑制剂）和Z-VAD-fastatin（泛半胱天冬酶抑制剂）分别在ASC寡聚化之前和之后阻断了muplant-NLRP 3依赖性细胞死亡。通过sh-RNA敲低ASC和caspase-1揭示了ASC在NLRP 3诱导的坏死细胞死亡中是必需的，而caspase-1不是。我们从几次观察中判断NLRP 3-PYD寡聚化诱导的细胞死亡方式为坏死，但是当NLRP 3-PYD寡聚化时，我们观察到半胱天冬酶-3和PARP的活化，这在细胞凋亡中观察到，而在tet-on系统的突变NLRP 3表达中没有观察到。这表明该NLRP 3-PYD寡聚化模型不能是NLRP 3活化的良好模型。我们使用气囊模型进行中性粒细胞浸润测定。该测定显示，NLRP 3介导的坏死细胞死亡在没有IL-1β的情况下导致嗜中性炎症反应。

Mutant-NLRP3 expression by Tet-on system induced necrotic cell death, while WT did not. We showed that CA074-Me(casepsin B inhibitor)and Z-VAD-fmk(pan-caspase inhibitor)blocked the mutant-NLRP3 dependent cell death before and after ASC oligomerization, respectively. Knocking down of ASC and caspase-1 by sh-RNA revealed that ASC was required in NLRP3-induced necrotic cell death, whereas caspase-1 was not. We judged the manner of cell death induced by NLRP3-PYD oligomerization as necrosis from several observations, but when NLRP3-PYD was oligomerized, we observed the activation of caspase-3 and PARP, which is observed in apoptosis and was not observed in mutant NLRP3 expression by tet-on system. This indicates that this NLRP3-PYD oligomerization model cannot be a good model of NLRP3 activation. We performed neutrophil infiltration assays using an air-pouch model. This assay showed that NLRP3-mediated necrotic cell death resulted in a neutrophilic inflammatory response without IL-1β.